Rainbow Electronics AT75C220 - Manual (Page 142)

AT75C220
142
WD Clock Mode Register
Name: WD_CMR
Access: Read/write
Reset Value:0
• WDCLKS: Clock Selection
• HPCV: High Preload Counter Value
Counter is preloaded when watchdog counter is restarted with bits 0 to 11 set (FFF) and bits 12 to 15 equaling HPCV.
• CKEY: Clock Access Key
Used only when writing WD_CMR. CKEY is read as 0.
0x06E: Write access in WD_CMR is allowed.
Other value: Write access in WD_CMR is prohibited.
WD Control Register
Name: WD_CR
Access: Write-only
• RSTKEY: Restart Key
0xC071 = Watchdog counter is restarted.
Other value = No effect.
31 30 29 28 27 26 25 24
– – – – – – – –
23 22 21 20 19 18 17 16
– – – – – – – –
15 14 13 12 11 10 9 8
CKEY
7 6 5 4 3 2 1 0
CKEY – HPCV WDCLKS
WDCLKS Clock Selected
0 0 ACLK/8
0 1 ACLK/32
1 0 ACLK/128
1 1 ACLK/1024
31 30 29 28 27 26 25 24
– – – – – – – –
23 22 21 20 19 18 17 16
– – – – – – – –
15 14 13 12 11 10 9 8
RSTKEY
7 6 5 4 3 2 1 0
RSTKEY